G'day Guys,
I have been taking apart old home theatre amps a bit recently for chassis, heatsinks and power transformers etc.
I have accumulated a huge stash of generic imperial(?) screws that seem to be used across all of the home theatre amps.
There is a 7mm m3 screw beside it for scale.
Is anybody able to tell me what this thread is so that I can find a tap for it?
I have been taking apart old home theatre amps a bit recently for chassis, heatsinks and power transformers etc.
I have accumulated a huge stash of generic imperial(?) screws that seem to be used across all of the home theatre amps.
There is a 7mm m3 screw beside it for scale.
Is anybody able to tell me what this thread is so that I can find a tap for it?
I don't really know, but those threads remind me of alpine ski binding screws. Were they screwed into nylon inserts or standoffs? Almost look like they could be self tapping.
They use them just about everywhere on the chassis and heatsinks.
Tapped holes of course, I don't think these are self tapping.
Tapped holes of course, I don't think these are self tapping.
They certainly look like self-tapping to me...
If you want to be sure, you‘d have to measure them with a thread-template ( Gewindeschablone – Wikipedia )
Or you could provide yourself a collection of possibly fitting screws and try them (but that a dumb proposal)
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They are a common form of self-tapping screws. Therefor you will not find a matching tap.
To use them, you need to drill a hole at, or very slightly smaller than, the core diameter (the diameter at the base of the threads) of the screw.
Self-tappers are only suitable for use in thin sheet steel or soft metals such as aluminium alloys.
To use them, you need to drill a hole at, or very slightly smaller than, the core diameter (the diameter at the base of the threads) of the screw.
Self-tappers are only suitable for use in thin sheet steel or soft metals such as aluminium alloys.
One constant feature of DIY Audio is that people loves to guess or offer advice based on insufficient data.
A caliper will tell you all you need and then some.
As in "peaks" diameter, "valleys/throughs" diameter and thread pitch.
Guessing from a fuzzy picture? .... gimme´ a break!!!
A caliper will tell you all you need and then some.
As in "peaks" diameter, "valleys/throughs" diameter and thread pitch.
Guessing from a fuzzy picture? .... gimme´ a break!!!
It's not at all fuzzy on the screen I'm viewing it on. From the thread form it is clear that they are self-tappers.
Jmfahey probably meant „fuzzy“ like M2.5 x 0.45 or M3 or !?!, like here: Spezialgewinde or ANSI External Screw Threads Size Tolerances Chart - Engineers Edge
(I‘m still convinced they‘re self-tapping
[emoji3])
I would call those thread forming screws:
Self-tapping screw - Wikipedia
Used in the same way as self tapping, but no swarf to short the circuitry
Brian
Self-tapping screw - Wikipedia
Used in the same way as self tapping, but no swarf to short the circuitry
Brian
That´s not the main problem.
Anybody can see they are self tapping.
By "fuzzy" I mean screw thread - pitch - diameter being guessed by comparison to a nearby
The question is:
Can any of you answer that based on data given?
Enlarge the picture 10X so now you can measure on screen with a ruler.
Oh, now picture is FUZZY
myleftear got it 🙂
Again, a caliper answers with precision 🙂
No "guessing"
Anybody can see they are self tapping.
By "fuzzy" I mean screw thread - pitch - diameter being guessed by comparison to a nearby
on a picture.
The question is:
Can any of you answer that based on data given?
Enlarge the picture 10X so now you can measure on screen with a ruler.
Oh, now picture is FUZZY
myleftear got it 🙂
Again, a caliper answers with precision 🙂
No "guessing"
... you shouldn‘t use those screws anymore, except maybe for repairing the old wooden frame that fell off the wall when you enjoyed your new amplifier [emoji16] (but not for metal because the „blades“ got dull)
Of course, regardless of thread pitch, self tapping / thread forming screws has no associated off the shelf tap. No guessing.
I always called those sheet metal screws. TO me "self tapping" refers to the machine screws with the tapered ends and carved out flutes so they dug out threads in the hole sides.
SO ther is no tap and die for those threads.
And I will wager my lunch money they are metric. ANything like "home theater" stuff made in Asia will not use imperial hardware.
And my actual favorite shop tip: When returning a sheet metal or wood screw to its hole, turn it backwards first, until it drops into the old threads. THEN tighten it. Don't cut fresh threads each time.
SO ther is no tap and die for those threads.
And I will wager my lunch money they are metric. ANything like "home theater" stuff made in Asia will not use imperial hardware.
And my actual favorite shop tip: When returning a sheet metal or wood screw to its hole, turn it backwards first, until it drops into the old threads. THEN tighten it. Don't cut fresh threads each time.
They're not self tappers. They never carved a thread hole anywhere. As the op mentioned, accumulated from "taking apart amps". They are simply sheet metal screws designed to fasten sheet metal amp covers to sheet metal chassis. The holes they go in are pre-drilled/punched.😎
The only thing I have to measure on sheet metal screws (besides length), would be the minor diameter.
That’s going to pretty much be the size of the hole that you will want.
That would be the diameter of the screw shank, as if the threads were gone.
That’s going to pretty much be the size of the hole that you will want.
That would be the diameter of the screw shank, as if the threads were gone.
ABSOLUTELY agree!!!! Wonderful tip.
I do exactly that when I repair anything with screws into plastic. Back it until it drops, then proceed..
Jn